I may try to return the PNY card... I am already having problems with MP3 skipping on my Sandisk. I am going to try to test the write performance using my USB2 card reader, and see if the write performance is really that bad...

I informally tested the write performance of my 256mb PNY SD card and the 512md Sandisk SD card. I used a PQI USB 2.0 card reader with my Dell 2.5 GHz P4 with USB 2.0. I tested transferring 70 GB of mp3 files to and from the cards.

Read performance was about the same.
Deleting took slightly longer on the PQI card.
Writing was a whole different story:
Sandisk: 30sec
PNY: 1min 45 seconds!

Sandisk was 300% faster than PNY, using the USB 2.0 card reader. Using a USB 1.0 card reader, you are limited by the transfer rate of USB 1.0, so the difference between the cards is minimal, but when you are using USB 2, you see the PNY card really sucks.

That being said, it was really cheap ($50), and I may end up using it for MP3 playback, but I will never buy PNY again, at any price.

Just got my SanDisk 512MB from Amazon. Popped it in the SD reader that is built in to my Toshiba laptop (I've had the laptop for almost two years and thought I would never use the SD slot). I copied over 480MB of MP3s in just a few minutes. Nice.

Why are my numbers so much lower than the other ones posted here for SanDisk 256MB?? Does it matter if the card has data already on it or if it's empty? How bad does performance need to be before actually considering the SD card as "defective"?

Originally posted by Loki Sunrider I bought a Kingston 512 card from NewEgg.com for $124 dollars.
<snip>But it took 12 hours to sync them over to my Treo 600.
<snip>Each one took about 1 hour to sync over. I think they are taking up a total of 168 megs on my sd card.

WOW, 12 hours!!! You might want to consider a card reader for your computer, especially if you plan on transferring mp3 files a lot. Readers are pretty cheap. I just backed up a full 256M SD card to my computer via a card reader (rather than via a hotsync).